The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense investigation. Non-invasive methods for examining tissue are palpation, X-ray, MRI, CT, and ultrasound imaging. When the physician suspects that a tissue may contain cancerous cells, a biopsy may be done either in an open procedure or in a percutaneous procedure. For an open procedure, a scalpel is used by the surgeon to create a large incision in the tissue in order to provide direct viewing and access to the tissue mass of interest. Removal of the entire mass (excisional biopsy) or a part of the mass (incisional biopsy) is done. For a percutaneous biopsy, a needle-like instrument is used through a very small incision to access the tissue mass of interest and to obtain a tissue sample for later examination and analysis. The advantages of the percutaneous method as compared to the open method are significant: less recovery time for the patient, less pain, less surgical time, lower cost, less risk of injury to adjacent bodily tissues such as nerves, and less disfigurement of the patient's anatomy. Use of the percutaneous method in combination with artificial imaging devices such as X-ray and ultrasound has resulted in highly reliable diagnoses and treatments.
Generally there are two ways to obtain percutaneously a portion of tissue from within the body, by aspiration or by core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into small enough pieces to be withdrawn in a fluid medium. The method is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core sampling, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors present in the patient, and no single procedure is ideal for all cases. However, core biopsies seem to be more widely used by physicians.
Recently, core biopsy devices have been combined with imaging technology to better target the lesion. A number of these devices have been commercialized. One such instrument type is the BIOPTY gun, trademark of C.R. Bard, Inc. and described in U.S. Pat. Nos. 4,699,154 and 4,944,308 as well as in U.S. Reissued Pat. No. Re. 34,056. The BIOPTY device is spring-powered, and each time a sample is to be taken the breast or organ must be punctured again upon re-insertion of the device. Another product is the TRU-CUT needle, trademark of C.R. Bard, Inc. The TRU-CUT needle collects a single core of tissue using a pointed stiletto with a side-facing notch to receive tissue near its distal end and an outer, sharpened sliding cannula.
To overcome operator error associated with these devices, and to enable multiple sampling of the tissue without having to re-puncture the tissue for each sample there was a desire for an automated device which took multiple samples with a single puncture. One such commercially available product is marketed under the trademark name MAMMOTOME, Ethicon Endo-Surgery, Inc. An embodiment of such a device is described in U.S. Pat. No. 5,526,822 issued to Burbank, et al, on Jun. 18, 1996, and is hereby incorporated herein by reference.
As seen from that reference, the MAMMOTOME instrument is a type of image-guided, percutaneous, coring, breast biopsy instrument. It is vacuum-assisted, and some of the steps for retrieving the tissue samples have been automated. The physician uses this device to capture “actively” (using the vacuum) the tissue prior to severing it from the body. This allows for sampling tissues of varying hardness. The device can also be used to collect multiple samples in numerous positions about its longitudinal axis, and without needing to remove the device from the body. These features allow for substantial sampling of large lesions and complete removal of small ones.
Co-pending application 60/240,877 filed Oct. 13, 2000 which is hereby incorporated herein by reference, describes other features and potential improvements to the MAMMOTOME device including a molded tissue cassette housing permitting the handling and viewing of multiple tissue samples without physical contact by the instrument operator. Another described therein is the interconnection of the housing to the piercing needle using a thumbwheel, to permit the needle to rotate relative to the housing, and preventing the vacuum tube from wrapping about the housing. During use, the thumbwheel is rotated so that the device rotates within the lesion, and samples can be taken at different points within the lesion.
In actual clinical use for breast biopsy the MAMMOTOME instrument (probe and driver assembly) is mounted to the three axis positioning head of an x-ray imaging machine. The three axis positioning head is located in the area between the x-ray source and the image plate. The x-ray machines are outfitted with a computerized system which requires two x-ray images of the breast be taken with the x-ray source at two different positions in order for the computer to calculate the x, y and z axis location of the suspect abnormality. In order to take the stereo x-ray images the x-ray source must be conveniently movable. The x-ray source therefore is typically mounted to an arm which, at the end opposite the x-ray source, is pivotally mounted to the frame of the machine in the region of the image plate.
The mounting of the device to an X-Ray machine has caused some difficulty in operating the thumbwheel. During a breast biopsy procedure, the operator has limited space to work in and it can be difficult for the operator to grasp and manually rotate the thumbwheel. Additionally, for the upright X-ray applications the operation of the thumbwheel causes the operator to be close to the patient's face. This can be awkward or difficult to manage, and can be uncomfortable for the patient. Lastly, the operator's hands can come in contact with bodily fluids and tissue during the biopsy procedure and these contaminants may be passed on to the surface of the thumbwheel.
Therefore, there has been a need for a biopsy device of the type described above, similar to the MAMMOTOME, which has a thumbwheel that automatically rotates after each sample is obtained. If such a device were to utilize existing rotational components for the additional task of rotating the needle aperture, the need for an extra shaft or gear is eliminated. Therefore the size of the device is reduced, creating more space for the manual rotation, but moreover it offers the operator the option of automatic rotation.